This disclosure relates to an on-board inert gas generation system for an aircraft. More specifically, the disclosure relates to a method and system for controlling a temperature of an air separation module within the system.
On-board inert gas generation systems are used in aircraft to provide inert gas to various locations within the aircraft, such as cargo areas or fuel tanks. In one prior art arrangement, the system includes two compressors arranged in series for providing non-enriched air to the air separation module. The air separation module produces nitrogen enriched air as the inert gas.
It is desirable to provide the non-enriched air to the air separation module within a desired operating temperature range to produce the nitrogen enriched air. A heat exchanger is typically arranged in a ram air duct in fluid communication between the compressors and the air separation module to cool the non-enriched air. The non-enriched air is cooled when ram air flows through the heat exchanger, thus maintaining the non-enriched air within the desired operating temperature range.
Some aircraft operating conditions would result in the non-enriched air reaching a temperature greater than the desired operating temperature range unless the non-enriched air entering the air separation module is cooled. For example, during conditions in which the temperature of the non-enriched air becomes undesirably hot, such as when the aircraft is on the ground and there is no airflow through the ram air duct, the non-enriched air must be cooled by other means. To this end, an approach has been used to cool the non-enriched air prior to reaching the air separation module by providing bleed air to an ejector that induces an airflow across the heat exchanger. The bleed air is supplied by either an engine or one of the compressors, which introduces inefficiencies to the aircraft.
What is needed is an efficient method and system to control the temperature of the air separation module.